Patent EP-1089290-A1 (EP)
Inventor: ZINK SEBASTIEN
IPC: G11C16/24
Filed: 2000-09-05
Abstract: The columns register of a memory in the form of integrated circuit is of EEPROM technology type, and the method for writing a data word with 2p bits, where p is an integer, comprises the following steps: (i) erasing all cells of the word; (ii) loading 2q data to the same number of high-voltage latches (HV1,HV3,HV5,HV7), and loading 2p-2q other data to that number of low-voltage latches (LV0,LV2,LV4,LV6); (iii) programming 2q cells of the words memory (M0,M2,M4,M6) as a function of stored data in the high-voltage latches; and the following steps repeated 2p-q-1 times: (iv) loading 2q other data in the high-voltage latches, which were loaded to the low-voltage latches in step (ii); and (v) programming 2q other cells of the words memory (M1,M3,M5,M7) as a function of data stored in the high-voltage latches. The columns register comprises 2q high-voltage latches, where q is an integer strictly less than p, where each high-voltage latch comprises the means for high voltage storage for the storage of a binary datum, as high programming voltage, e.g. 18 V, or zero voltage, coupled to the mean for conditional and selective switching for carrying the high programming voltage to the determined bit line; and 2p-q low-voltage latches, where each low-voltage latch comprises the means for low voltage storage for the storage of a binary datum as low supply voltage, e.g. 5 V, or zero voltage, and thee means for coupling to the input of one of the high-voltage latches, which is activated for loading the binary datum stored in the low-voltage latch. In particular, the integer p = 3, and q = 2. The means for conditional and selective switching comprise a MOS transistor with n-type conductivity channel, connected by the gate to the output of high-voltage storage means, by the drain to high programming voltage, and to the bit lines (BL0,BL1) by the intermediary of MOS transistors for the purpose of insulation of the bit lines in the read mode and the selection of particular bit line in the write mode. The first and second loading means share at least one loading transistor (TC1,TC2), which are activated simultaneously by at least first loading signal (LOAD1,LOAD2) applied to the gate of loading transistor, connected to a transistor for word selection (TS1) with the gate receiving the word selection signal (COL). The means for high voltage storage in the high-voltage latches comprise two inverters in CMOS technology in antiparallel connection between the high programming voltage and the ground, and the means for low voltage storage comprise analogous components connected between the low supply voltage and the ground. An integrated circuit memory comprises a planar memory with at least 2p cells connected to the respective bit lines, and proposed columns register. A memory comprises several words memory on the same line, and the means for writing to certain or all of words memory simultaneously. The programming step (v) is followed by a step (vi) for bringing to zero the means for storage of low-voltage and high-voltage latches. The steps (i) and/or (iii) to (v) are operated simultaneously for several or all of words memory of the same line of memory cells.